class_docstr: A dummy ensemble model.
code: def forward(self, X):
      return torch.stack(
          [torch.einsum("...d,dm", X, self.a[i]) for i in range(4)],
          dim=-3,
      )
  
file_path: botorch/test/models/test_ensemble.py
imports: import torch
  from botorch.models.ensemble import EnsembleModel
  from botorch.utils.testing import BotorchTestCase
label_desc: Use image node_id 2 for calling the DummyEnsembleModel obj's underlying member method code with example usage: obj.forward(X) and returns: torch